It is of vital importance, before attempting to
operate your engine, to read the general
'SAFETY INSTRUCTIONS AND WARNINGS'
section on pages 2-6 of this booklet and to strictly
adhere to the advice contained therein.
●
Also, please study the entire contents of this
instruction manual, so as to familiarize yourself
with the controls and other features of the
engine.
●
Keep these instructions in a safe place so that
you may readily refer to them whenever
necessary.
●
It is suggested that any instructions supplied
with the aircraft, radio control equipment, etc.,
are accessible for checking at the same time.
CONTENTS
SAFETY INSTRUCTIONS AND WARNINGS
ABOUT YOUR O.S. ENGINE
INTRODUCTION
INSTALLATION OF THE ENGINE
INSTALLATION OF SILENCER
NEEDLE-VALVE LOCATION
BEFORE STARTING
PLUMBING AND
FUEL TANK POSITION
ADVICE ON SELECTION OF FUEL,
GLOW PLUG & PROPELLER
10
14
2~6
9
~
~
~
10
12
12
22
STAR TING THE ENGINE
7
8
9
RUNNING-IN (Breaking-in)
TROUBLE SHOOTING WHEN THE
ENGINE FAILS TO START
CARE AND MAINTENANCE
ENGINE EXPLODED VIEW &
PARTS LIST
THREE VIEW DRAWING
OPTIONAL PARTS & ACCESSORIES
1
14
~
20
20
~
22
21
23
24
~
27
28~29
30
SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S. ENGINE
Remember that your engine is not a "toy", but a highly efficient internalcombustion machine whose power is capable of harming you, or others, if it is
misused.
As owner, you, alone, are responsible for the safe operation of your engine, so act
with discretion and care at all times.
If at some future date, your O.S. engine is acquired by another person, we would
respectfully request that these instructions are also passed on to its new owner.
The advice which follows is grouped under two headings according to the
degree of damage or danger which might arise through misuse or neglect.
WARNINGS
These cover events which
might involve serious (in
extreme circumstances, even
fatal) injury.
NOTES
These cover the many other
possibilities, generally less obvious
sources of danger, but which, under
certain circumstances, may also
cause damage or injury.
2
WARNINGS
Never touch, or allow any object to come
•
into contact with, the rotating
propeller and do not crouch
over the engine when it is
running.
A weakened or loose propeller may
•
disintegrate or be thrown off and, since
propeller tip speeds with powerful
engines may exceed 600 feet(180 metres)
per second, it will be understood that
such a failure could result in serious
injury, (see 'NOTES' section relating to
propeller safety).
Model engine fuel is poisonous. Do not
•
allow it to come into contact with the eyes
or mouth. Always store it in a
clearly marked container and
out of the reach of children.
Model engine fuel is also highly
•
flammable. Keep it away from open flame,
excessive heat, sources of sparks, or
anything else which might ignite
it. Do not smoke or allow anyone
else to smoke, near to it.
•
Never operate your engine in an enclosed space. Model engines, like automobile engines, exhaust deadly carbonmonoxide. Run your engine only in an
open area.
Model engines generate considerable
•
heat. Do not touch any part of your
engine until it has cooled. Contact with
the muffler (silencer),
cylinder head or exhaust
header pipe, in particular,
may result in a serious burn.
3
NOTES
This engine was designed for model
•
aircraft. Do not attempt to use it for any
other purpose.
Mount the engine in your model securely,
•
following the manufacturers' recommendations, using appropriate screws and locknuts.
Be sure to use the silencer (muffler)
•
supplied with the engine. Frequent
exposure to an open exhaust may
eventually impair your hearing.
Such noise is also likely to cause
annoyance to others over a wide area.
If you remove the glowplug from the engine
•
and check its condition by connecting the
battery leads to it, do not hold the plug with
bare fingers.Use an appropriate tool or a
folded piece of cloth.
Fit a top-quality propeller of the diameter
•
and pitch specified for the engine and
aircraft. Locate the propeller on the shaft so
that the curved face of the blades faces
forward-i.e. in the direction of flight. Firmly
tighten the propeller nut, using the correct
size wrench.
4
NOTES
Always check the tightness of the propeller
•
nut and retighten it, if necessary, before
restarting the engine, particularly in the
case of four-stroke-cycle engines. If a
safety locknut assembly is provided with
your engine, always use it. This will prevent
the propeller from flying off in the event of a
"backfire", even if it loosens.
If you fit a spinner, make sure that it is a
•
precision made product and that the slots
for the propeller blades do not cut into the
blade roots and weaken them.
Preferably, use an electric starter. The
•
wearing of safety glasses is also strongly
recommended.
Discard any propeller which has become
•
split, cracked, nicked or otherwise rendered
unsafe. Never attempt to repair such a
propeller: destroy it. Do not modify a propeller
in any way, unless you are highly experienced
in tuning propellers for specialized
competition work such as pylon-racing.
Take care that the glow plug clip or battery
•
leads do not come into contact with the
propeller. Also check the linkage to the
throttle arm. A disconnected linkage could
also foul the propeller.
After starting the engine, carry out any
•
needle-valve readjustments from a safe
position behind the rotating propeller. Stop
the engine before attempting to make other
adjustments to the carburettor.
5
NOTES
Adjust the throttle linkage so that the engine
•
stops when the throttle stick and trim lever
on the transmitter are fully retarded.
Alternatively, the engine may be stopped by
cutting off the fuel supply. Never try to stop
the engine physically.
Take care that loose clothing (ties, shirt
•
sleeves, scarves, etc.)do not come into
contact with the propeller.Do not carry loose
objects (such as pencils, screwdrivers, etc.)
in a shirt pocket from where they could fall
through the propeller arc.
Do not start your engine in an area
•
containing loose gravel or sand.
The propeller may throw such material in
your face and eyes and cause injury.
For their safety, keep all onlookers
•
(especially small children) well back (at
least 20 feet or 6 meters) when preparing
your model for flight. If you have to carry
the model to the take-off point with the
engine running, be especially cautious.
Keep the propeller pointed away from you
and walk well clear of spectators.
Warning! Immediately after a glowplug-
•
ignition engine has been run and is still
warm, conditions sometimes exist whereby
it is just possible for the engine to abruptly
restart if the propeller is casually flipped
over compression WITHOUT the glowplug
battery being reconnected. Remember this
if you wish to avoid the risk of a painfully
rapped knuckle!
6
INTRODUCTION
The "LA-S Series" engines are designed for control line
models. They have broad power characteristics which
are suitable for both trainer models and stunt models.
A separate needle-valve is mounted at the rear, where
manual adjustment is safely away from the rotating
propeller.
The 'midnight blue' external finish may be
decolorized by very high surface temperature or
by certain solvents. Such decolorization does not
affect engine perfor-mance, however.
Connect the short length of fuel tubing supplied
securely between the fuel outlet and the fuel inlet. In
the event of the tube becoming damaged, it should be
replaced with a suitable length of best quality 5mm
ODX2mm ID silicone tubing. Use similar material to
connect the fuel inlet nipple to the fuel tank.
Length
~
15LA-S
25LA-S
40/46LA-S
52mm
51
~
56mm
55
~
66mm
65
7
Cylinder head
Venturi
Propeller nut
Crankshaft
Fuel inlet
Drive Hub
Propeller washer
Glowplug
Fuel outlet
Needle valve
Cover Plate
Silicone Tube
Crankcase
INSTALLATION
Installation in the model
A typical method of beam
mounting is shown below,left.
At least
12mm(1/2")
At least
12mm(1/2")
Make sure that the mounting beams are parallel
and that their top surfaces are in the same plane.
CORRECT
O.S. radial motor mount
(Available as an optional extra part.
See parts list)
Rigid hardwood
(e.g. maple)
INCORRECT
How to fasten the mounting screws.
Tighten second nut firmly
3mm steel nuts
Spring washer or
lock washer
down onto first nut.
Tighten this nut first.
Steel washer
3mm steel screw
Hardwood mounting beams
3mm steel Allen screw
Spring washer
Hardwood such as
cherry or maple.
Front view
Side view
Top surfaces are in the
same plane.
Top surfaces are not
in the same plane.
Re-align the surfaces
as necessary
Opposite beam
Top surfaces
are not in the
same plane.
Engine does
not seat firmly.
O.S. radial motor mount
(cast aluminum)
8
NEEDLE-VALVE EXTENSION
The needle-valve supplied with these engines is
designed to incorporate an extension so that, when
the engine is enclosed within the fuselage, the
needle-valve may be adjusted from the outside.
Cut a commercially available rod to the required
length, bend one end to an L shape, insert it into
needle's center hole and secure it by tightening the
set-screw in the needle-valve knob with 1.5mm. Allen
key.
INSTALLATION OF SILENCER
The angled exhaust of the silencer can be rotated to
any desired position in the following manner:
1) Loosen the locknut and assembly screw.
2) Set the exhaust outlet at the required position by
rotating the rear part of the silencer.
3) Re-tighten the assembly screw, followed by the
locknut. The standard silencer is quite effective but
reduces power to some degree.
Assembly screw
Exhaust pressure nipple
Reminder!
Model engines generate considerable heat. Do
not touch any part of your engine until it has
cooled. Contact with the muffler (silencer),
cylinder head or exhaust header pipe, in
particular, may result in a serious burn.
Cone baffle
Turn to requlred position
Exhaust outlet
NEEDLE-VALVE LOCATION
As delivered from the factory, the MAX-40LA & 46LA
have the needle-valve assembly installed vertically.
However, if more convenient for a particular
installation, the needle-valve may be reinstalled
horizontally.
The procedure for relocating the needle-valve is as
follows:
9
Locknut
Remove the two cover-plate screws which secure
1.
the needle-valve assembly bracket, then carefully
remove the two screws by which the needle-valve
unit is attached to the bracket.
2.
Rotate the needle-valve unit through 90˚ and reattach it to the bracket in the required position.
Note:
As self-tapping screws are used for unit
attachment, screw them in carefully so that screw
threads match those of the unit body precisely.
3.
Finally, secure the complete assembly to rear cover
plate as before.
Needle Valve unit
Cover plate fitting holes
Needle-Valve
Assembly Bracket
Needle Valve unit attachment screws
Vertical position
Horizontal position
BEFORE STARTING
Tools, accessories, etc.
The following items are necessary for operating the
engine.
1 Fuel
Model glowplug engine fuel of good quality, preferably
containing a small percentage of nitromethane. (See
"Advice on selection of fuel, glowplug and propeller")
2 Glowplug
O.S. A3 glowplug is installed in the engine.
3 Propeller
Suggested size is 8 X4 (15LA-S), 9 X6 (25LA-S),11X5
(40LA-S), or 11X6 (46LA-S).
4 Glowplug battery
The power source for heating the glowplug may be
either a large heavy-duty 1.5volt dry cell, or preferably,
a 2-volt rechargeable lead-acid cell (accumulator).
If a 2-volt cell is employed,
use a resistance wire, as
shown, to reduce applied
voltage, otherwise the element
1.5 volt heavy-duty
dry battery
10
will overheat and burn out.
or 2 volt rechargeable
lead-acid cell (at least 5Ah)
Warning (Very hot)
Never touch
the nichrome
wire while
the battery is
connected.
Adjust applied voltage by
changing the position of clip
on resistance coil until
glowplug element is glowing
bright red.
Resistance coil
(nichrome wire)
Battery leads
Raise
voltage to
increase
brightness.
Lower voltage to
reduce brightness.
5 Plug wrench
Used for tightening glowplug. The O.S. long plug
wrench is available as an optional accessory.
6 Battery leads
These are used to conduct current from the battery to
the glowplug. Basically, two leads, with clips, are
required, but, for greater convenience, twin leads with
special glowplug connectors, as shown on the right,
are commercially available.
7 Fuel tank
For installation in the model, a 40cc(1oz.) for 15LA-S,
a 60cc(2oz.) for 25LA-S, a 120cc(4oz.)-140cc(5oz.) for
40.46LA-S, is suggested.
8 Fuel bottle or pump
For filling the fuel tank, a simple,
polyethylene "squeeze" bottle,
with a suitable spout,is all that is
required. Alternatively , one of the
purpose-made manual or
electric fuel pumps may be used
to transfer fuel directly from your
fuel container to the fuel tank.
9 Fuel can filter
Fit a filter to the outlet tube of
your refuelling container to
prevent entry of foreign
matter into the fuel tank.
(R/C clunk tank installation)
10 Silicone tubing
This is required for the
connection between the fuel
tank and engine.
11 Electric starter and
starter battery
An electric starter is
recommended for starting.
12V Battery
11
Fuel bulb
Battery leads
Fuel pumps
Electric
Fuel Can Filter
For tightening
glowplug
Manual
Starter
PLUMBING AND FUEL TANK POSITION
Make sure that there are no kinks or folds in the
plumbing.
(example)
Metal control line fuel tank installation
Note:
Control line models tend to receive more abrupt changes of
attitude than R/C models,which results in air bubbles being
drawn from the fuel tank. Pay careful attention to the
plumbing and fuel tank position.
Note: When cutting silicone tubing......
Silicone tubing
Use knife or
razor blade.
*If you should need to clean out silicone tubes, use methanol or
glow-fuel, not gasoline.
Measurement A (height from the
bottom surface of the mounting lug
to the center of the spray bar)
Make sure that the center of the spray
bar and tank are on the same line.
R/C clunk tank installation
5~8
15LA-S
25LA-S
40/46LA-S
A
mm
A
Do not use wire
cutters or pliers
11.5mm
12mm
13mm
Silencer (muffler) pressurized fuel system
To reduce variation in fuel "head" and ensure steady
fuel delivery at the carburettor, it is advisable to employ
a silencer (muffler) pressurized fuel system, i.e. to use
the silencer outlet nipple to pressurize the fuel tank as
shown at left.
ADVICE ON SELECTION OF FUEL, GLOWPLUG & PROPELLER
Fuel
Use a good quality commercial fuel or one of the blends
shown in the table. Fuel "A" is suitable for running-in and
ordinary use. Fuel "B" is for use when more power is required
and for improved flexibility. Note that even a small quantity
of nitromethane (3-5%) will improve flexibility, making the
needle-valve adjustment less critical and improving throttle
response. Use only materials of the highest purity. Synthetic
oils are permissible but are less tolerant of a "lean run" than
castor-oil. If, therefore, a synthetic lubricant is used in the
fuel, readjust the needle-valve to a slightly richer setting, as
a safety measure, in case the fuel/air mixture becomes too
lean through maneuvers in flight. If a more powerful fuel is
used, the engine should be checked out to make sure that
it is sufficiently run-in to operate on that particular fuel
without overheating. Do not use fuels containing less than
18% lubricant.
12
A
Methanol
Castor Oil
Nitromethane
Reminder!
Model engine fuel is poisonous. Do not
allow it to come into contact with the eyes or
mouth. Always store it in a clearly marked
container and out of the reach of children.
Model engine fuel is also highly flammable.
Keep it away from open flame, excessive
heat, sources of sparks, or anything else
which might ignite it. Do not smoke, or allow
anyone else to smoke, near to it.
PROPELLER
Suggested propeller sizes are given in the table.
As the ideal propeller diameter, pitch and blade area
vary according to the size, weight and type of model,
final propeller selection will require in flight
experimentation.
75%
20%
5%
B
65%
20%
10%
Reminder!
Never touch, or allow any object to come
into contact with, the rotating propeller and
do not crouch over the engine when it is
running.
15LA-S
25LA-S
40LA-S
46LA-S
GLOWPLUG
An O.S. A3 glowplug is installed in the engine.
Other recommended O.S. plugs are Nos.8 and A5.
Carefully fit plug finger-tight, before final tightening
with the correct size plug wrench.
Running-in
8✕4
✕6
9
✕5
11
✕6
11
Aerobatic & Sport
~
8
✕4
✕6,10✕5
9
~
✕5
11
~
✕6
7,12✕5~6
11
The role of the glowplug
With a glowplug engine, ignition is initiated by the
application of a 1.5-volt power source. When the battery
is disconnected, the heat retained within the combustion
chamber remains sufficient to keep the plug filament
glowing, thereby continuing to keep the engine running.
Ignition timing is 'automatic' : under reduced load,
allowing higher rpm, the plug becomes hotter and,
appropriately, fires the fuel/air charge earlier;
conversely, at reduced rpm, the plug become cooler and
ignition is retarded.
13
6
6
Glowplug life
Particularly in the case of very high performance
engines,
glowplugs must be regarded as expendable
However, plug life can be extended and engine
performance maintained by careful use, i.e.:
Install a plug suitable for the engine.
•
Use fuel containing a moderate percentage of
•
nitromethane unless more is essential for racing
events.
Do not run the engine too lean and do not leave the
•
battery connected while adjusting the needle.
When to replace the glowplug
Apart from when actually burned out, a plug may
need to be replaced because it no longer delivers its
best performance, such as when:
Filament surface has roughened and turned white.
•
Filament coil has become distorted.
•
Foreign matter has adhered to filament or plug
•
body has corroded.
Engine tends to cut out when idling.
•
Starting qualities deteriorate.
•
STARTING THE ENGINE
Preparations
1 Installing the glowplug
Install the washer on the glowplug and
screw carefully into cylinder-head,
making sure that it is not crossthreaded before tightening firmly.
Glow plug
Washer
2 Installing the propeller
First, mount the propeller on the engine by tightening
the prop nut or spinner-nut lightly, and make sure of
the position where compression is felt, turning the
propeller counter-clockwise slowly. Then tighten
firmly as explained below.
For accurately centering the
starter's rubber drive insert,
use an O.S. solid alloy
spinner-nut. (Available as an
optional extra part).
Alternatively, a spinner
assembly, enclosing the
propeller boss, may be
used, but make sure
that it is of sturdy construction and that the spinner
shell does not loosen when the starter is used.
Wrench
14
Warning: When using a spinner assembly, make
sure that the notches in the spinner shell are
large enough to clear the propeller blades and so
do not cut into and weaken the blade roots.
Tighten the spinner nut firmly so that compression is
first felt as indicated (i.e. with blades horizontal) when
turning the propeller in the direction of arrow.
3 Filling the fuel tank
Re-connect
delivery tube
to engine after
tank is filled.
Use a fuel can filter
(e.g. O.S. Super Filter).
Do not allow fuel to overflow into
silencer when refuelling, otherwise
engine may become flooded and
difficult to start.
Disconnect delivery tube
from the fuel inlet, and
connect it to the tubing
from the fuel pump.
Fuel pump
Do not let dirt or
dust enter fuel can.
Fuel (model
glow-plug
engine fuel)
4 Opening and closing of the needle-valve
Close
Open
Turn needle-valve clockwise to close (for leaner mixture).
Turn needle-valve counter-clockwise to open (for richer mixture).
5 Setting the needle-valve
Open the needle-valve 3 turns (for 15LA-S), 1 turns (for
25,40,46LA-S) in the direction of arrow from the closed
position.
Close Open
The position where the needle-valve stops is the fully closed
position. It may be convenient to remember the position of the
mark or set-screw at this time.
15
1
2
6 Priming
Place your finger
over the venturi
to choke intake.
Turn the propeller
two revolutions
while watching
the fuel line.
Turn the engine for 3
to 4 seconds by an
electric starter without
connecting glowplug
battery.
Fuel Tube
Fuel inlet
Fuel will flow
from tank to
venturi as
propeller is
turned.
Hold model securely when starting
7
Glowplug battery.
Place as far to the
rear as possible.
Starter
Be careful not
to be hit by propeller!
8 Heat glowplug
Connect battery leads as shown
(polarity is immaterial.)
16
Assistant should hold
the model so that it
cannot move forward
when the engine starts.
Assistant
Starting battery
9 Apply electric starter
Bring the starter into contact with the spinner nut or
spinner and depress the starter switch for one or two
seconds. Repeat if necessary. When the engine fires,
withdraw the starter immediately.
Attention: Never place your finger over the
carburettor intake when applying the starter. Such an
action will cause an excess quantity of fuel to be
drawn into the cylinder and result in hydraulic lock
that may damage the engine.
Warning!
Since a control line engine is started with the
throttle fully opened and reaches full rpm right
after starting, be sure to hold the model securely.
10
Engine starts
If the engine does not start, refer to the TROUBLE
SHOOTING CHART .
BEWARE of
the rotating
propeller.
In the interests of safety, keep your face and other parts of the
body away from the vicinity of the propeller.
17
11
Needle-valve adjustment(1)
Then gradually close the needle-valve until the exhaust sound
changes from an irregular pitch (four-cycle) to a steady pitch
(two-cycle).
Close the needlevalve
gradually until the engine
sound is changing from a
four-cycle into a twocycle in pitch.
13
Needle-valve adjustment(2)
As the needle-valve is closed beyond the initial readjustment,
the r.p.m. of the engine will be increased and a continuous
high-pitched exhaust note, only, will be heard.
Key to the needle-valve
adjustment.
(Turn 20-30˚ at a time.)
Listen to the sound
carefully.
12
Disconnect battery leads
Disconnect the battery leads
from the engine with care so
that the plug clip does not
touch the rotating pro-peller.
If the engine stops when battery leads are disconnected, close
the needle-valve a little (approx. 45˚) further, and restart the
engine.
Turn the needle-valve 20-30˚ in the direction of arrow, and wait
momentarily for the change of r.p.m.
After the r.p.m. of the engine increases, turn the needle-valve
another 20-30˚ and wait for the next change of r.p.m.
As the speed of the engine does not instantly change with
needle-valve readjustment, small movements, with pauses
between, are necessary to arrive at the optimum setting.
IMPORTANT NOTE
When fine-tuning the needle-valve to reach peak performance, take care not to run the engine too lean
and cause it to overheat.
Be sure to observe the simple running-in procedures
described on Page 20.
18
14
Needle-valve adjustment(Summary)
77
Practical best(optimum) needle-valve setting
Clear, high-pitched two-stroke
exhaust note
Maximum rpm setting("Lean").
20~30˚
5
Intermittent, high-pitched
two-stroke note superimposed
on low "four-stroke" sound.
4
Disconnect battery leads from
glowplug at about this point.
3
Exhaust note starts to change.
Note: Although this is a two-stroke engine it fires like
a four-stroke at these rich needle-valve settings-i.e.
ignition of the fuel charge takes place at every fourth
stroke of the piston instead of at every second
stroke.
NOTE: The above sketch is for reference purposes only.
Actual needle positions may differ from those shown.
2
The engine may stop if the battery leads
are disconnected from the glowplug while
the engine is running rich.
v
e
R
o
t
E
e
n
n
i
g
s
s
t
p
o
1
"Rich" needle-valve
setting when starting
the engine.
t
t
e
r
d
a
t
s
o
t
s
.
n
e
s
o
i
t
a
u
e
l
r
o
c
e
d
On starting from cold, with the needle-valve
set at the rich starting position:
a good deal of white smoke is emitted, accompanied by
a relatively low-pitched "four-stroke" exhaust note.
As the needle-valve is closed and the r.p.m. increases:
an intermittent high-pitched two-stroke note will be superimposed
on the low-pitched "four-stroke" note.
Exhaust smoke will be less dense and grey in colour.
Further needle-valve closure:
exhaust note is now a steady high-pitched sound,rising
higher in pitch as needle-valve is closed and
The grey smoke will be lighter.
(However, make sure that engine is fully run in.)
Finally:
maximum rpm is reached and will fall off (or engine will
stop) if needle -valve is closed any further.
Exhaust gas will be very light.
Now, re-open needle-valve 20-30˚
This will produce the practical best (i.e. optimum)
rpm setting (lower than maximum rpm).
A light grey exhaust emission may be observed.
Take note of this position of the needle-valve.
19
increase.
Subsequent starting procedure
Once the optimum needle-valve setting has been
established (see "Needle-valve adjustmentSummary") the procedure for starting is simplified as
follows:
1) Open the needle-valve one half-turn (180˚) from
the optimum setting.
2) Energize the glowplug and apply the starter.
When the engine starts, re-adjust the needle-valve
to the optimum setting.
Note: When re-starting the engine on the same
day, provided that atmospheric conditions have
not changed significantly, it may be practicable to
re-start the engine on its optimum (running)
setting. Also, if the engine is being re-started
immediately after a run (i.e.hot), priming should
not be necessary.
15
How to stop the engine
To cut off the fuel supply, pinch the fuel delivery tube to the
venturi.
14
RUNNING-IN ("Breaking-in")
All internal-combustion engines benefit, to some
degree, from extra care when they are run for the first
few times - known as running-in or breaking-in. This is
because the working parts of a new engine take a little
time to settle down after being subjected to high
temperatures and stresses. However, because O.S.
engines are made with the aid of the finest modern
precision machinery and from the best and most suitable
materials, only a very short and simple running-in
procedure is required and can be carried out with the
engine installed in the model.The process is as follows:
1) Start the engine and, with the throttle fully open,
open the needle-valve an extra half turn (180˚)
from the optimum setting. This will produce a rich
mixture that will result in cooler running. Allow the
engine to run out a full tank on the ground. (Avoid
dusty surroundings.)
2) Now fly the model with the needle-valve re-set 2030 degrees open from the optimum setting ( i.e.
40-60˚ from the highest rpm setting).
3) Close the needle-valve very slightly on successive
flights so that the engine is running on its optimum
needle setting at the fifth or sixth flight.
20
TROUBLE SHOOTING WHEN THE ENGINE FAILS TO START
Four key points
For quick, reliable starting, the following four conditions are required.
1 Good compression. 2 Adequate "glow" at glowplug. 3 Correct mixture.
4 Sufficient electric starter rotating speed.
If the engine fails to start, or does not keep running after being started, check symptoms against the
following chart and take necessary corrective action.
Note: The most common causes of trouble are marked with three asterisks, the less common problems
with one or two asterisks.
Symptom
Engine fails
to fire.
Factor
1
2
3
Cause
Sluggish rotation
Glowplug battery
discharged.
Glowplug element is
burned out
Something wrong with
battery leads.
Engine "flooded" due to
excessive priming.
Insufficient priming.
......
......
.....
....
....
.....
Corrective action
Recharge the electric starter battery.
Recharge lead-acid cell or replace dry battery. (Note: An unused, or
almost unused, dry battery may sometimes be of insufficient capacity if it is
"old stock".)
Replace glowplug. Check that applied voltage is not too high.
Check glowplug heating using other leads.
Close needle-valve fully and remove glowplug, then flip propeller to pump
out excess fuel. (Invert engine, if possible, while pumping out excess).
Re-start engine. (Priming is not necessary at this time.)
Repeat priming procedure referring to 6 Priming.
21
Symptom
Engine fires
intermittently but
does not run.
Engine fires once
or twice, then
fails to fire.
Engine starts but
revolutions decrease
and engine eventually
stops.
Engine starts,
then revolutions
increase and
engine cuts out.
Engine stops when
battery leads are
disconnected after
starting.
Factor
2
3
1
2
3
3
3
3
2
Cause
Incorrect heating of
glowplug.
Over priming.
Sluggish rotation.
Glowplug battery
discharged.
Insufficient priming.
Mixture too rich.
Fuel not reaching the
engine.
Mixture too rich.
Mismatch of glow plug and
fuel.
.....
........
......
......
.....
.......
.....
.......
Corrective action
Voltage too high or too low. Re-check and readjust referring to "BEFORE
STARTING" paragraph 4.
Continue flipping propeller. If engine does not start after more than 10 flips,
disconnect battery from glowplug and leave for a few minutes, then reenergize plug and flip prop again. If engine still does not start, remove
glowplug and pump out excess fuel by flipping prop quickly.
Then re-start. (Priming is not necessary.)
Recharge the electric starter battery.
Recharge lead-acid cell or replace dry battery.
(Note: An unused, or almost unused, dry battery may sometimes be of
insufficient capacity if it is "old stock".)
Repeat priming procedure referring to 6 Priming.
Close needle-valve half turn (180˚) and wait for several minutes then restart.(Priming is not necessary.)
Make sure that tank is filled with fuel. Check that there is not something
wrong with fuel tubing (kinked or split). Check that carburettor is not
clogged with dirt.
Close the needle-valve a little.
....
Change fuel or glowplug.
22
CARE AND MAINTENANCE
To ensure that you obtain long life and peak performance
from your engine, observe the following.
Avoid running the engine under dusty conditions.
1.
If necessary, lay a sheet of plywood or hard-board
in front and under the nose of the model when
starting the engine.
Foreign matter in the fuel can cause the venturi jet
2.
to be partially clogged.
Therefore:
rinse out the fuel tank with methanol or fuel before
•
installing it.
fit a fuel filter to the fuel delivery tube between tank
•
and venturi.
fit a fuel filter to the outlet of your squeeze bottle,
•
or to the pump inlet if you use a manual or electric
pump.
do not leave your fuel container open needlessly.
•
check filters periodically and clean them when
•
necessary.
3.
Do not leave raw fuel in the engine at the
conclusion of a flying session: it may cause
corrosion. The best practice is to disconnect the
delivery tube from the venturi while the engine is
running. Remaining fuel in the tank should also be
drained off.
Clean the exterior of the engine with a clean cotton
4.
cloth.If this is not done, oil and dirt will burn onto
the outside of the engine each time it is run and
the engine will soon become blackened.
If the engine is not in use for a while (more than
5.
two months) remove the glowplug and rinse out
the interior with kerosene (not gasoline), by
rotating the crankshaft. Shake out residue, then
inject light machine-oil through the plug hole and
carburettor intake, again rotating the shaft to
distribute the protective oil to all working parts.
Gasoline, thinner, kerosene and light machine oil
cause swelling and deterioration of plastic parts,
"O" rings and fuel tubing. Use methanol for
cleaning these parts.
Avoid unnecessary dismantling of your engine.
6.
23
EXPLODED VIEW
M.M2.6X10(15LA-S)
N.+M3X12(25LA-S)
1
(MAX-15/25LA-S)
w
2
e
24
5
6
8
7
✽
Type of screw C…Cap Screw M…Oval Fillister-Head Screw
3
-
0
9
=
F…Flat Head Screw N…Round Head Screw S…Set Screw
4
M3.5
B.M2.6X8
S.3X3
q
q
q
-1
-2
q
q
-4
-5
q
-3
ENGINE PARTS LIST
Description
1
Cylinder Head
2
Cylinder & Piston Assembly
3
Piston Pin
4
Connecting Rod
5
Venturi
6
Nozzle For Remote Needle
7
Propeller Nut
8
Propeller Washer
9
Drive Hub
Thrust Washer
0
Crankcase
-
Crankshaft
=
25
Cover Plate Assembly
q
Cover Plate
q
-1
Ratchet Spring
q
-2
Needle
q
-3
"O" Ring
q
-4
Set Screw
q
-5
Head Gasket
w
Screw Set
e
(MAX-15/25LA-S)
15LA-S
21754000
21753000
21706000
21205040
21712010
21381970
20810007
21109005
21758000
21620006
21751000
21752000
21757000
21757100
21781970
21714100
21713000
Glow Plug A3
871 Silencer
Pressure Fitting
Assembly Screw
Fixing Screw(N.+M2.6X25 2pcs.)
21225000
22681957
22325300
21125409
E-2030 Silencer
Pressure Fitting
Assembly Screw
Fixing Screw(N.+M3X27 2pcs.)
Specifications are subject to alteration for improvement without notice.
Code No.
25LA-S
22554000
22553000
22606009
22405013
22312000
21381980
23210007
24009000
22558000
22020001
22551000
22302000
22557000
22557100
26711305
24081970
24981837
26381501
22564000
22563000
71605300
22325020
22681957
22325310
22625404
EXPLODED VIEW
N.+M3X12
1
(MAX-40/46LA-S)
2
26
5
8
7
✽
Type of screw C…Cap Screw M…Oval Fillister-Head Screw
3
4
-
0
9
6
F…Flat Head Screw N…Round Head Screw S…Set Screw
M3.5
q
t
=
N.+M3X8
e
S.3X3
r
r
r
-4
-5
r
-6
w
r
r
-3
-2
r
-1
ENGINE PARTS LIST
(MAX-40/46LA-S)
Code No.
40LA-S
24004000
24003010
23356000
24001001
23364000
27
Description
1
Cylinder Head
2
Cylinder & Piston Assembly
3
Piston Pin
4
Connecting Rod
5
Venturi
6
Nozzle For Remote Needle
7
Propeller Nut
8
Propeller Washer
9
Drive Hub
0
Thrust Washer
-
Crankcase
=
Crankshaft
q
Gasket Set
w
Cover Plate
e
Needle Valve Assembly B racket
r
Needle Valve Assembly
r
-1
Needle
r
-2
"O" Ring
r
-3
Set Screw
r
-4
Ratchet Spring
r
-5
Needle Valve Body
r
-6
Needle Valve Body Retaining Screw
t
Screw Set
Glow Plug A3
E-3030 Silencer
Pressure Fitting
Assembly Screw
Retaining Screw(2pcs.)
Specifications are subject to alteration for improvement without notice.
46LA-S
24004100
24003100
45806000
24005000
23312000
21381980
23210007
24009000
24008000
22020001
24001100
23302000
24014100
24007110
24007120
26582900
24081970
24981837
26381501
26711305
26582910
26582920
24013000
71605300
23325020
22681957
23325320
22625404
MAX-15/25LA-S THREE VIEW DRAWING
15LA-S SPECIFICATIONS
Displacement
■
Bore
■
Stroke
■
Practical R.P.M.
■
Power output
■
Weight
■
2.49 cc (0.1517 cu.in.
15.2mm (0.598 in.
13.7mm (0.539 in.
~
18,000 r.p.m.
2,500
0.41 bhp / 17,000 r.p.m.
129.5g (4.56 oz.
25LA-S SPECIFICATIONS
Displacement
■
Bore
■
Stroke
■
Practical R.P.M.
■
Power output
■
Weight
■
4.07 cc (0.249 cu.in.
18.0mm (0.709 in.
16.0mm (0.630 in.
~
16,000 r.p.m.
2,000
0.6 bhp / 15,000 r.p.m.
185.5g (6.54 oz.
)
)
)
)
)
)
)
)
28
Dimensions(mm)
( )15LA
MAX-40/46LA-S THREE VIEW DRAWING
40LA-S SPECIFICATIONS
Displacement
■
Bore
■
Stroke
■
Practical R.P.M.
■
Power output
■
Weight
■
6.49 cc (0.396cu.in.
21.2 mm (0.835in.
18.4 mm (0.724in.
~
16,000 r.p.m.
2,000
1.0 bhp / 15,000 r.p.m.
267.5g (9.43oz.
46LA-S SPECIFICATIONS
Displacement
■
Bore
■
Stroke
■
Practical R.P.M.
■
Power output
■
Weight
■
7.64 cc (0.467cu.in.
23.0 mm (0.906in.
18.4 mm (0.724in.
~
16,000 r.p.m.
2,000
1.2 bhp / 15,000 r.p.m.
263.5g (9.29oz.
Dimensions(mm)
)
)
)
)
)
)
)
)
29
O.S. GENUINE PARTS & ACCESSORIES
RADIAL MOTOR MOUNT
■
(71909310) for 15LA-S
(71908100) for 25LA-S
(71906200) for 40,46LA-S
SUPER SILENCER
■
E-2030S
E-3030S
(22325030) for 25LA-S
(23325030) for 40,46LA-S
SILENCER EXTENSION
■
ADAPTORS
(21125108) for 15LA-S
(22325100) for 25LA-S
(23325100) for 40,46LA-S
LONG PROPELLER NUT SET
■
(73101000) for 25 46LA
BUBBLESS WEIGHT
■
(Bubble Eliminating Tank Weight)
(71531000)
30
GLOW PLUG
■
(71605300)
A3
SPINNER NUT
■
M5 (20824005) for 15LA-S
1
/ "-28
4
1
/ "-28(L)
4
LONG SOCKET WRENCH
■
WITH PLUG GRIP
(71521000)
SUPER FILTER (L
■
(72403050)
(23024008) for 25LA-S
(23024009) for 40,46LA-S
)
E
C
R
I
P
S
I
Y
O
T
I
N
L
A
U
Q
D
E
L
L
A
U
Q
E
N
U
&
P
E
R
F
O
R
M
A
N
C
E
E
S
T
A
B
L
I
S
H
I
N
G
T
H
E
R
S
A
T
D
A
N
C
Copyright 2000 by O.S.Engines Mfg. Co., Ltd. All rights reserved. Printed in Japan.
E
C
N
E
L
L
E
C
X
E
F
O
S
D
6-15 3-Chome Imagawa Higashisumiyoshi-ku
Osaka 546-0003, Japan
TEL. (06) 6702-0225
FAX. (06) 6704-2722
URL : http://www.os-engines.co.jp
110100
Loading...